Method of rebuilding a viaduct without interrupting service on the old structure

ABSTRACT

A method of rebuilding a viaduct without interrupting service on the old structure by over topping it with a new, higher viaduct well above existing traffic, includes the following:
     Erecting new span supporting columns arrayed along either side of the old viaduct.   New columns are temporarily connected to old viaduct to strengthen it for a temporary scaffold role transporting heavy subassemblies into position atop the new columns.   The subassemblies or their components would typically arrive at a staging area alongside the old viaduct for preparation and hoisting the subassemblies onto a high dolly atop the old viaduct.   The subassemblies are assembled into spans on the high dolly atop the old viaduct roadbed surface to transport and position the spans sequentially onto respective columns beginning with columns at extreme ends of the old viaduct and successively hoisting and transporting more subassemblies until a new higher viaduct roadbed is assembled well over the still functioning old viaduct.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC § 119(e) of U.S. Provisional Application No. 60/899,794, filed on Feb. 7, 2007, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Elevated roadways such as viaducts in service are often replaced due to age, ugliness, inadequate capacity, damage, seismic vulnerability, or combinations of the aforementioned. In areas of extensive development, disruption of surrounding infrastructure and interrupted traffic flow during reconstruction may well be more costly than the actual reconstruction costs.

Where conditions permit, a bypass of some sort, a parallel structure, may allow construction while service continues on the old viaduct. Where development is too dense along the route, one option would be to build high, directly above the existing in-service viaduct

OBJECTS AND SUMMARY OF THE INVENTION

Objects and advantages of the invention are:

-   -   By postponing demolition, impact on neighboring infrastructure         is minimized.     -   By continuing traffic on the old structure, area traffic flow         continues without disruption.     -   A higher, newer, safer, more beautiful structure adds value to         the community.     -   Supporting columns for a new, higher roadbed may be temporarily         connected to the old viaduct to temporarily reinforce it.

The objects and advantages of the invention are realized in a method of rebuilding a viaduct without interrupting service on the old structure by building a new, higher viaduct well above the existing viaduct insuring that the new roadbed is clear of traffic on the old viaduct.

First, new span supporting columns must be erected, arrayed along either side of the old viaduct. The new columns may be connected by a temporary means to the old viaduct to strengthen it for a temporary scaffold role carrying heavy new span-length roadbed subassemblies into positions atop the new columns. One or more subassemblies can be placed and assembled onto a high dolly riding on the old viaduct roadbed surface to transport and position the span-length subassemblies. The spans are placed sequentially over respective columns beginning with columns at extreme ends of the old viaduct and successively transporting more spans until the new, higher viaduct roadbed is fully assembled over the still functioning old viaduct.

The spans, limited in number, require only a limited number of traffic interruptions during nights or slack traffic periods. Once placed upon the columns the heavy roadbed sections no longer burden the old viaduct or threaten traffic.

Another object is to realize the economic advantages of repetitive remote fabrication (optionally in a modern shipyard) of an essentially complete roadbed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of a viaduct undergoing reconstruction according to the invention, with spans being assembled on a dolly, then being moved to and placed on columns starting above either end of old viaduct.

FIG. 2 is a representation of the second of two ½ span subassemblies being hoisted onto a dolly.

FIG. 2 also represents more clearly to the right, a second dolly with a ½ span aboard.

FIG. 3 is a close-up wire frame representation of the transport dolly carrying the first ½ span and awaiting the second ½ span and showing the arrays of wheelsets or air cushion pallets that spread the great load of a span onto the old roadbed.

FIG. 4 is a close-up wire frame of a dolly designed to make turns on a viaduct that is not straight showing the arrays of wheelsets or air cushion pallets set into two diamond shaped “bogies” (see Wikipedia) swivel mounted to the dolly.

FIG. 5 is a representation of 2 dollies with diamond shaped bogies, one traveling straight and a second traveling around a curve.

FIG. 6 is a representation of bogies alone traveling around a curve within the confines of the roadway.

FIG. 7 is a blown up representation of the omni directional spring suspended wheelsets or air cushion pallets shown in previous large arrays.

FIG. 8 is a representation of the joined ends of two adjoining spans bearing upon a span support beam atop paired new columns.

FIG. 9 is a representation of the dolly placed beside viaduct while traffic flows on old viaduct.

FIG. 10 is a representation of a span held in cantilever by cablestays over one end of a new viaduct and a partial view with the new viaduct dropped slightly exposing the arrays of wheelsets or air cushion pallets in place.

FIG. 11 is a representation of a span held in cantilever by cablestays over one end of a new viaduct and then lowered at one end by jacks onto the continuation roadbed.

REFERENCE NUMERALS IN DRAWINGS 1. Old viaduct 2. New columns 3. Roadbed span (1 or more subassemblies) 4. Subassemblies (components delivered by barge or land transported to lift point staging area) 5. Crane 6. Dolly 7. Span support beams 8. Arrays of wheelsets or air cushion pallets (spring suspended 8b) 9. Diamond shaped bogies 10. Confines of the roadbed 11. Steering means for swiveling the bogies 12. Cablestay mast 13. Far end span and transition ramp13a 14. Tall jacks 15. Continuation roadbed

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A method of rebuilding an old viaduct 1 (FIG. 1) without interrupting service on the old structure by over topping it with a new, higher viaduct above existing traffic, includes the following:

Erecting new roadbed columns 2 arrayed along either side of the old viaduct to support new roadbed spans 3. The next step is temporarily connecting the new columns to the old viaduct. This reinforces the viaduct to use it temporarily as a scaffold to transport heavy subassemblies 4 into position atop the new columns. The subassemblies 4 or their components would typically arrive at a staging area alongside the old viaduct where they are prepared and hoisted by crane 5 onto a high dolly 6 atop the old viaduct. The subassemblies (one or more sections), are quickly turned into a complete span on the high dolly 6 atop the old viaduct roadbed surface. The dolly transports and positions the spans sequentially into final position atop span support beams 7 each atop respective column pairs. The sequence begins with columns at extreme ends of the old viaduct and continues until a new higher viaduct roadbed is assembled well over the still functioning old viaduct. A span support beam acts as a bearing surface for joined ends of two adjoining spans. One span support beam 7 a is attached to the dolly under the near end of the span to be transported. The other end of the span is moved by the dolly till it can be placed upon the exposed edge of the span support beam 7 b supporting the previous span. (Also see FIG. 8) Between span transport events the inactive dolly is placed beside viaduct while traffic flows on the old viaduct. (See FIG. 9)

DESCRIPTION OF OTHER EMBODIMENTS

The dolly is supported for movement along the roadbed surface with means for reduced friction movement along that surface. Typically, arrays 8 (FIGS. 3 & 4) of rubber tired wheels, wheels on steel rails, or air cushion pallets provide for low friction motion. All wheelsets or air cushion pallets may be spring suspended 8 b to compensate for roadbed irregularities on the old viaduct. (FIG. 7)

A modified dolly is provided with arrays of omni directional wheelsets (each with one or more wheels on casters) or air cushion pallets set into two diamond shaped bogies 9 swivel mounted to the base of the dolly to allow it to make turns within the confines of the roadbed 10 on a viaduct that is not straight. (See FIGS. 5 and 6)

The transport dolly with diamond shaped bogies is provided steering means 11 (hydraulic cylinders or other means) for swiveling the bogies independent of the dolly.

Economic advantages are obtained if repetitive remote fabrication is done of an essentially complete span or half span (optionally in a modern shipyard) especially where delivery of subassemblies can be made by barge to the lifting point.

Where span subassembly component delivery to the lift point is by land transport, preassembly at the lift point is desirable so that minimal assembly time is required upon the traffic blocking viaduct dolly.

In order to transport spans to act as ramps at either end of the new high viaduct, a modified transport method is implemented. A span launching truss made of roadbed spans moves spans beyond either end of the new viaduct. A span launching truss is made up of several roadbed spans 3 atop the new viaduct roadbed and stiffened by a central cablestay mast 12 atop those several spans with cablestays arrayed along the two end spans. Launching spans beyond the length of the old viaduct without interrupting service on the old viaduct is a means to launch a roadbed ramp to lower or to raise the new viaduct roadbed path to the roadbed continuing beyond the old viaduct. It is also a means to lengthen the viaduct. The process includes the following:

Additional subassemblies 4 sufficient to assemble approximately 3 (See FIG. 10) spans are placed atop the new viaduct also atop an array of wheelsets or air cushion pallets 8 interspersed between the new viaduct roadbed and the spans. The assembly of spans is transported to an end of the new viaduct. Next a cablestay mast is erected centered upon a central span directly behind the far end span 13 of the transported spans and cablestays are arrayed along the length of the far end span and along the rear span. The cablestays are tensioned to put the two end spans in suspension. The central span bears down on a large array of wheelsets or air pallets in order to transmit the mast load to a large area of the new viaduct roadbed. The assembled cablestays, mast and spans, are moved one span length beyond the end of the new viaduct (See FIG. 14) putting the far end suspended span in cantilever. Tall span supporting jacks 14 lower the cantilevered span into level alignment with the new viaduct roadbed. The process is repeated as often as necessary while the extended spans are level. A requisite length of transition ramp 13 a extending to the roadway continuation roadbed 15 is created by raising or lowering the far end of the requisite length of spans with the tall supporting jacks whereupon supporting columns or columns and span supporting beams replace all tall jacks. 

1. A method of rebuilding an elevated roadway or viaduct without interrupting service on the old viaduct by over topping it with a new, higher viaduct above existing traffic, comprising the steps of: a) erecting new span supporting columns arrayed adjoining the route of said old viaduct, b) assembling roadway subassemblies on a high dolly atop the old viaduct roadbed surface to transport and position the subassemblies sequentially onto respective said columns beginning with columns at extreme ends of the old viaduct and successively transporting more subassemblies until said new higher viaduct roadbed is assembled at a height that does not interfere with traffic on the still functioning old viaduct and, whereby normal traffic on the old viaduct can continue except during brief transport of subassemblies.
 2. The method of claim 1 in which the new columns are connected temporarily to the old viaduct to strengthen it for a temporary scaffold role to carry heavy subassemblies into positions atop the new columns beginning at said extreme ends of the old viaduct.
 3. Said dolly of claim 1 in which arrays of wheelsets or air cushion pallets are set into the dolly bottom to provide a low friction means to transport heavy loads.
 4. Said dolly of claim 1 in which arrays of omni directional wheelsets or air cushion pallets are set into two diamond shaped bogies swivel mounted to the base of the dolly designed to make turns on a viaduct that is not straight.
 5. Said dolly of claim 4 provided steering means for swiveling the said bogies independent of the dolly.
 6. A method of rebuilding an old viaduct without interrupting service on the structure by building a new, higher viaduct directly above said old viaduct, above existing traffic, comprising the steps of: a) erecting new span supporting columns arrayed along either side of an old viaduct, b) temporarily connecting said new columns to the old viaduct to strengthen it for a temporary scaffold role to carry heavy subassemblies into position atop the new columns beginning at extreme ends of the old viaduct, and c) assembling said subassemblies on a high dolly atop the old viaduct roadbed surface to transport and position the subassemblies sequentially onto respective columns beginning with columns at said extreme ends of the old viaduct and successively transporting more subassemblies until said new higher viaduct roadbed is assembled well over the still functioning old viaduct.
 7. Said dolly of claim 6 in which arrays of wheelsets or air cushion pallets are set into the dolly bottom to provide a low friction means to transport heavy loads.
 8. Said dolly of claim 6 in which arrays of wheelsets or air cushion pallets are set into two diamond shaped bogies swivel mounted to the base of the dolly designed to make turns on a viaduct that is not straight.
 9. Said dolly of claim 8 provided steering means for swiveling the said bogies independent of the dolly.
 10. A method of launching spans of a new viaduct erected above an old viaduct beyond the ends of said old viaduct without interrupting service on the old viaduct as a means to lengthen the viaduct or to launch a roadbed transition ramp to lower or to raise the said new viaduct roadbed path to the roadbed continuing beyond the old viaduct roadbed, comprising the steps of: a) placing additional subassemblies sufficient to assemble approximately 3 spans atop said new viaduct also atop an array of wheelsets or air cushion pallets interspersed between the new viaduct roadbed and said subassemblies, b) transporting said spans to an end of the new viaduct, c) erecting a cablestay mast centered upon a central span directly behind the far end span of the transported spans, d) arraying cablestays along the length of the said far end span and along the rear span, e) tensioning said cablestays to put the two end spans in suspension, f) moving the assembled cablestays, mast and spans one span length beyond the end of the new roadbed putting the far end suspended span in cantilever, g) lowering the far span with tall supporting jacks into level alignment with the new viaduct roadbed, h) repeating the process as often as necessary while the extended spans are level, and i) creating said transition ramp of requisite length by raising or lowering the far end of the transition ramp with said tall supporting jacks and erecting supporting columns or columns and span supporting beams to replace all tall jacks. 